The American needed just 59 minutes to see off the second-seeded Australian and set up a showdown with Lucie Safarova, who didn't even drop a game in her victory over Slovenia's Polona Hercog.

Williams managed five breaks of serve and hit 29 winners in total to improve her record against Stosur to 6-3, though one of those defeats did come in last year's US Open final.

However the 13-time grand slam champion had recorded a straight-sets triumph in their last meeting, which came in Miami 11 days ago.

Stosur had beaten Venus Williams in the quarter-finals to spoil the chance of an all-Williams showdown, but was simply no match for her semi-final opponent.

"I have to say, this is probably the best match I've played in my career, either in a long time or it's up there in the top five," said Williams.

"It was one of those days I could have done anything against anybody."

Next up for Williams will be Safarova, who recorded an emphatic 6-0 6-0 victory over Hercog, the conqueror of third-seeded Marion Bartoli in the third round, in 64 minutes.